This invention relates to an invalid transferring apparatus and more particularly to a wheel chair construction facilitating convertability of such chair into a wheeled stretcher and vice versa. In this connection it should be understood that hospital beds and the like intended for use of bed type patients are elevated to an approximate counter height to enable nurses, doctors and persons attending the needs of such patients to more easily do so without bending over or squatting to move or manipulate the patient in such bed. Wheel chairs, on the other hand, have their seats more nearly disposed at chair height wherein, the patients legs are so disposed, that their feet are but a short distance from the floor. It will therefore be appreciated that the wheeled stretcher contemplated by the instant application is of the type to support a patient at substantial bed level, i.e., at a considerable higher elevation than that of the seat of the wheel chair when the apparatus is converted into such form.
It will therefore be appreciated that the conversion of the wheel chair to a bed type stretcher, and vice versa entails an elevator mechanism operatively associated with the seat and bed for changing the elevation, thereof, in the course of convertability.
Several prior patients disclose structure for elevating the seat per se of such type of chair so that the back and foot rests follow the independent adjustment into a horizontal support. In this art it is customary to have the foot or leg rests as well as the back of the chair hingedly connected to the chair seat and adapted to level off with the latter when it is elevated to its uppermost position as a part of the bed with the leg rests and chair back.
Other patents in the prior art coordinate the pivotal or hinged connections between the seat, back and leg rests with the frame of the vehicle type chair to utilize the parallelogram leverage afforded thereby to raise and/or lower the seat relative to the frame. This puts an excessive load upon the leverages in the course of elevating the seat with patient thereon. Likewise, the lowering of a patient on the bed-like surface to a sitting position can become quite abrupt and fraught with shock, and unnecessary shaking up of the patient during the conversion.
The present invention seeks to alleviate the foregoing problems and yet attain a smooth operating elevator mechanism controlled by the chair back, i.e., using the latter as an operating lever for the elevator while changing the chair to a bed or the bed to a chair.